


Two Parts of One Whole

by kayecho



Category: Ao no Exorcist | Blue Exorcist
Genre: Biting, Blood, Codependency, Dubious Consent, Incest, M/M, Masturbation, Plot What Plot/Porn Without Plot, Shameless Smut, Tails, Twincest
Language: English
Status: Completed
Published: 2017-05-19
Updated: 2017-05-19
Packaged: 2018-11-02 08:58:31
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,329
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10941198
Author URL: https://archiveofourown.org/users/kayecho/pseuds/kayecho
Summary: When Rin is alone, he loses control and nothing is enough to satisfy him.





	Two Parts of One Whole

**Author's Note:**

> Well, I guess this is my first Ao no Exorcist fic, and it's smut. It's shameless, plotless smut, with two brothers mindlessly fucking each other. I should apologize, but I really don't feel very bad about making it happen. Written in one sitting, no beta, thrown to the internet without any editing. Hope you enjoy the ride.

_Choking. Suffocating. Overwhelmed. Feverish. Hot. Desperate. ___

__The first time Rin felt this way he had only just turned sixteen. It had been a long, difficult mission. It had been his first time out as a Lower Rank Exorcist, his first mission after graduating from Exwire. It had been long, grueling. There was very little sleep, and he had been determined to complete the mission without resorting to his flames. He had already proven his competencies with his flames, but it was something else entirely to do so without them. By the time he had returned home, his whole body was aching and he felt it like a pulse in his core before he lost control, before he woke up with little memory of what had transpired around him. He had awoke to the dormitory room torn to shreds with his brother standing at the door looking infuriated._ _

__It only happened once more after that, some six months later, though thankfully he had somehow managed to clean up before Yukio could see the mess he had made._ _

__Rin still didn't understand what it was, what had happened those two times, but he was grateful that they never happened again. At least, he had been grateful. Past tense._ _

__The feeling washed over him again, starting like a throbbing he could feel in the marrow of his bones. It dragged a groan from deep inside him, visceral and primal in nature. The sensation gripped at him. It felt as though a vice was wrapped around his body, choking him. The fabric of his clothes were suffocating him, making it hard to breathe. He clawed at his throat, at the shirt collar, already undone, tie already loose around his neck. It wasn't enough. He felt the sweat drip down his back as he tore at the buttons of his shirt. He couldn't hear the sound they made as they hit the hard wood floor; he could only hear the rushing of the blood in his veins, making his whole body flush._ _

__Back arching off the bed, Rin ran his hands down the front of his naked torso. The dark room was illuminated a faint blue, flames dancing from skin were the sharp points of his claws cut through, drawing blood. He bit down on his bottom lip, muffling a moan as his hands found the buckle of his trousers, as they undid the button, as they dragged down the zipper, relieving the pressure on his aching cock. It strained against the thin cotton of his boxers, fabric already wet with precum. Rin grasped himself, dragged his hand over the length, fist tight. It only took two, three pumps before he was cumming with a gasp, every muscle in his body tensing at once._ _

__Under normal circumstances, once would have been enough. On a normal day, a normal morning, a normal evening. Once after browsing a magazine or the internet. These were not normal circumstances._ _

__Rin shoved at his trousers, pushing them down out of the way, over the jut of his tail and the curve of his ass. He kicked them out of the way, shrugged out of his shirt. He lay naked on the sheets of his bed, in the same room he'd been sharing with his brother for years. He moaned, rolling over and shoving his face into the pillows. He could feel the soft fur of his tail as he intentionally dragged it up along the inside of his thighs. Over the years he had gotten more and more used to his tail, able to make use of it than for it to hang around like a useless appendage, and he found that he more than enjoyed the feeling of it brushing against his skin. On a normal day it would be a gentle tease, enough to get him ready as he stood under the hot spray of his nightly shower. Today it made his whole body buzz with need. His skin prickled with goosebumps. He bit into the pillow, tearing the fabric with his fangs._ _

__His cock was already hard, and he shoved it against the mattress, hips thrusting, seeking friction. He dug his toes into the sheets and raised his ass into the air, as if searching for something, anything. He turned his head enough to shove his fingers in his mouth, ignoring the way his fangs bit into his skin, the way his claws raked against his tongue. He sucked on them until they were wet with spit before reaching, pushing into his asshole with a needy whine._ _

__It wasn't enough. It wasn't hot enough, it wasn't thick enough. He plunged his spit-slick finger in and out of his hole. He pushed in another. He stretched himself. He felt the hot, tight muscle fight against him. Wetness dripped down his hand. He came with a shout around his fingers, feeling his cock throb with release._ _

__Rin pulled his fingers free. He was panting as he tore at the sheets, cock still hard, as though he could find something to soothe his ache. It still wasn't enough. He remembered it from two years ago, the way he endured it without any satisfaction. the way he spent what felt like eternity in a constant limbo of need._ _

__His tail hung between his legs, batting back and forth, swatting at the inside of his thighs. He dragged the soft fur of his tail, damp with sweat, up. He rubbed his taint, the space between his ass and his balls. He teased the hole, the pucker of muscle, feeling it tense and clench and seek intrusion. He groaned and shoved his ass against his the tip of his tail, pushing into himself with the flexible appendage. More. More._ _

__Desperate, Rin tried to fuck himself with his own tail, pulling it out, pushing it back in. The furs dragged against his wet insides, creating hot friction. It burned and ached but it did nothing to satisfy him. He bit into the pillow, he tore into the feathery-down. He whined, and shoved and pushed and wrapped his hand around his cock, tugging and pulling, shameless with his hunger. He was so lost, he didn't hear the heavy footfalls, the creaking sound of the old dormitory door, the sound of a gun being cocked, but he wasn't so lost that he didn't hear the voice. It cut through his senses like a red-hot knife._ _

__"Niisan!"_ _

__Rin pulled his tail free from his ass, rolled over onto his back, looked towards the yellow light of the hallway, at the figure that stood there. Yukio stood, pistol ready, both hands raised, finger straight across the trigger guard. His face was pale. His eyes were wide._ _

__It was Rin's brother. His perfect, broad shouldered, tall, strong, proud, intelligent, gifted brother. The brother he had spent so many years trying to protect. The brother who tried so hard to protect him in return. The brother who was almost everything he wasn't. The brother who was everything he wanted._ _

__Yukio lowered the gun, had the sense to not drop it in his shock. He hurried to his brother's side. His voice was concerned. His hands hesitated. "Niisan! What's happening? Did someone do this to you?"_ _

__Rin looked up into those warm eyes, a deeper, warmer blue than his own. He reached for him, traced his fingers over the sharp point of Yukio's newly developed demon ears. Seeing his brother, touching him, it allowed him just the slightest bit of sense in the fog of arousal, enough so he could manage more than a guttural sound of need. "Yukio-- yukio... Fuck. I want-- I need."_ _

__"What? What do you want? What do you need?" Yukio was trying to avoid looking at anything other than his brother's eyes, trying to ignore his blatant nudity, his turgid cock, his flushed skin, the self inflicted wounds, the blood and shining slick of cum between his legs. He had a wealth of information about demons. He was a genius about demons, but Rin was a special case. Rin was something no other demon was, at least no other demon other than himself. The scent of sex in the air made his skin prickle into goosebumps._ _

__"You. You. I want. I need." Rin grabbed at the lapels of Yukio's thick coat, dragged him closer, dragged him half on the bed. He leaned up and caught his brother's lip with his teeth. He bit into the skin, before closing that last hair of distance, shoving his mouth against Yukio's, tasting the hot iron of blood. He shoved his tongue in past those lips, he moaned as he felt the wet heat surround the flexible muscle._ _

__Yukio tried to pull back, tried to break away. He pushed his hands against Rin's shoulders and shoved. Their lips tore apart, and he could not tell if the gasp he heard was his own or his brother's. His heart was thundering in his chest. He feel it throbbing against his rib cage, and his shoulders were heaving as he tried to catch his breath. He couldn't help himself, he let his gaze sweep across his brother's body, took in the details, watched that damp tail thumping impatiently against the bed._ _

__Rin was both frustrated and annoyed at being rejected. He huffed and then snarled before throwing himself at his brother again. He pushed his face into the crook of his neck, his nimble fingers undoing the buttons of his coat. He breathed in the scent of Yukio, hot and musty and spicy in a way that reminded him of Shiemi. The thought of her hands in his brother made his chest tighten and he parted his lips before sinking his teeth into the soft flesh of his brother's neck._ _

__At the sharp bite of fangs in his skin, Yukio froze. His whole body tensed at once in a combination if nerves and pleasure. Every sensible part of his brain was firing at once. This was his brother. They were both men. This was wrong. He had to stop him. But deep down, underneath all that sense was his primal, demonic self that awoken later than his brother's. It hungered for this. It wanted it. It needed it. He felt his brother's wicked tongue slide across his skin, felt his brother's hot, calloused fingers wrap around his cock, pulling it free from his trousers. He hadn't even noticed his brother undressing him._ _

__"Mine," Rin snarled as he licked his way up Yukio's neck. "Mine," he repeated as his mouth found Yukio's ear, as he bit and sucked and tugged with his teeth on the fleshy lobe. His hands roamed eagerly across his brother's skin, feeling the hard muscle shift beneath his touch. He raked his claws possessively down Yukio's chest, drawing blood as he pumped his fist over the length of Yukio's hard cock._ _

__Yukio shuddered at the feeling of those claws, at the mix of pain and pleasure. He reached  
for his brother's shoulders a second time, tried to summon the strength to push him away, but he couldn't. He couldn't bear to reject him, despite every reason that he should. Not with his brother looking like this. Not with his brother's hands and mouth on his skin like this. Not with his brother whispering possession in his ear like a selfish, greedy child. "Niisan...."_ _

__Rin responded immediately to the sound of Yukio's voice, at how it sounded less like protest and concern and more like desire. He practically purred against his brother's temple, nipping at the skin there before he pushed him down against the mattress and straddled him with his naked body. Rin licked his lips slowly, as he rocked his ass against Yukio's cock._ _

__Yukio's realized, perhaps too late what not protesting meant as he watched his brother grip his cock, as he watched his brother line himself up; watched him push himself down onto his length. It was slow, it was hot. He groaned and bit his lip. Rin arched and made a high pitched sound of pleasure. His tail stood at rapt attention, matching the cock that leaned against his stomach, leaking as he moved. "Wait..."_ _

__Rin shook his head. This was what he wanted, this feeling of fullness, the feeling of his brothers cock deep inside him, hot and hard and filling a void that no one else could fill. It was as though they were two pieces of one whole reuniting. All that wanting, all that needing and desperation, solved in this one moment. He moved his hips slowly, rocking up and down over Yukio's cock. His body shuddered with every motion._ _

__"Niisan..." Yukio's protest was weak. It was that last shred of sense in him trying to stop this, but as he watched his brother move on his cock, watched the blue flames flicker from his body, felt the tongues against his own skin, that shred seemed to dissolve. It burned away with his own blue flames and he gripped his brother's hips, dug his own claws into his skin. He thrust his hips up hard and suddenly._ _

__Rin felt the motion in his core, a shock of pleasure that caught him off guard and made him gasp, eyes wide, body going rigid. It was enough to bring him back for just the briefest of moments, enough to make him aware of his brother beneath him; his brother fully transformed and fangs bared, cock buried in Rin's ass. He was aware enough to yelp in surprise as his brother pushed at him, bowled him over, shoved him into the mattress._ _

__Yukio thrust into Rin, pounded his hips against his brother's ass. Their lips met, and Yukio devoured the sound of his brother's moan, their tongues slid together, hot and wet. Fangs dragged against lips and skin and knocked together. Rin wrapped his arms around his brother's neck, hooked his ankles behind his brother's back. He was clinging to him._ _

__"More," Rin managed with a gasp as their mouths broke apart. "More. Harder..."_ _

__Yukio pushed his face into the crook of Rin's neck and dug his teeth possessively into the soft flesh there. The taste of his brother's blood filled his mouth and he only moved faster, complying with Rin's demands._ _

__For several moments they moved as one, bodies rocking and thrusting and moving, a blur of wet heat and blood and flames. They panted and clung to each other, connecting in the most primal of ways. They kissed again and again, mouths seeking each other out, as though they were not willing to be parted, until Rip's whole body suddenly seized. His head fell back and every part of him tightened around his brother. He came without any words, without any sound, his cock pulsing between their bodies, his ass shuddering around his brother's cock._ _

__Yukio somehow found the strength to speak, his voice a breathy whisper of warning against his brother's ear. "Niisan, I'm... You have to let go, I'm going to..."_ _

__"No."_ _

__The word of protest was enough to make Yukio pause. "What?"_ _

__Rin clung tighter to his brother. There was a clarity to his voice that had been missing all night. "No. I won't let go. You're gonna stay right where you are. You are gonna cum inside me."_ _

__Yukio groaned a the the words, the way they drove straight through him like a red hot poker. His lips found Rin's temple, skin damp with sweat, and he kissed him as he started moving again. "I... You are going to regret this..."_ _

__"Don't... Don't tell me what I am and am not gonna regret, Yukio..." Rin's words were broken by the sound of his panting as he tried to keep up with his brother's thrusting, his arms and legs tight around him._ _

__Yukio's breathing hitched, and he groaned and bit Rin's cheek as he shoved in as deep as he could manage, pressing his hips firmly against his brother's ass, and he came with a low, guttural moan that rumbled between them as he came. His cock throbbed and pulsed in Rin's ass, filling him with heat, dragging a whine from far back in his throat._ _

__The two stayed like this for what felt like an eternity, clinging to one another. Yukio buried inside of his brother; Rin refusing to let his brother go. Eventually, they slid apart, cock's softening. Cum slid wet and sticky from Rin's ass, cloudy and tinged pink with blood. Yukio took stock of the moment, surveying the scene around them, the condition of the bed beneath them. The room stank of sex, the sheets were torn and stained. His brother was battered, bruised and covered in open wounds, looking as though he had just emerged from a fight. Yukio's condition wasn't much better, though he lacked the same prominent bite marks, including the one on Rin's cheek. He pushed at his glasses consciously, realizing now how smudged they had gotten in the moment, before reaching for his brother, using a clean corner of the sheet to wipe at one of the open sores. "Look at you, Niisan. You look awful."_ _

__Rin didn't pull away from the touch, though he sighed and draped an arm over his eyes. "I feel," he was breathless as he spoke, still recovering, "Amazing and like shit at the exact same time."_ _

__Yukio hesitated, before he shifted on the bed. He bowed his head. "I'm sorry!"_ _

__"What the hell are you sorry for?" Rin tried to push himself up into a sitting position, and found himself flinching in pain instead, his hips and the small of his back already beginning to ache._ _

__"I-- I did such an awful thing to you!"_ _

__For a moment, Rin regarded his brother with one eyebrow raised, looking at him incredulously. It was almost too childish to hear and then he shook his head and laughed. "Goddamn it, Yukio. I wanted it. Fuck, I needed it." And when he said it, the gears in his head spun and then clicked into place, the realization of how and why he felt that way; how and why it only happened so many times in the past few years._ _

__The Okumura brothers were more than twins, they were more than attached at the hip. They were two parts of the same whole, two beings that never should have existed, and yet by the sheer force of their mother and by Satan himself they were born. As far as Rin was concerned, they spent every waking moment together, they lived together and they would die together. Twice when they was sixteen, they were forced to spend more than a week apart, both of them on their own missions. Twice when they were sixteen Rin was forced to live as though his brother weren't there for him at all times. Twice when they were sixteen he had lost control. Twice when they were sixteen he had come to when his brother reentered his life._ _

__This time Yukio had been away on a long mission. It was a month apart from his brother. His body was begging for his return, calling out to him in the only way it knew how. Rin leaned over and tackled his brother against the bed, despite the pain he felt shooting up his spine. He pulled Yukio into his arms, hugging him close. "Don't ever leave me again."_ _

__"Niisan..."_ _

__"If you do, I'm going to turn into that again."_ _

__Rin felt Yukio stiffen in his arms, and he squeezed him experimentally, suddenly worried. "Yukio?"_ _

__"That.... that... that really isn't much of a threat."_ _

__"What!?"_ _

__Yukio twisted in Rin's arms before managing to hug him back. He pressed his lips to Rin's sweat-damp forehead, and when he spoke, his words were a whisper, muffled against his brother's warm skin. "I won't want it if you don't want it, but I won't be able to find the strength to tell you I don't want it at all."_ _

**Author's Note:**

> "Like, comment and subscribe!" - Every youtuber ever.


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